rover JPL

3 Articles

Putting Perseverance Rover’s View Into Satellite View Context

March 30, 2021 by 3 Comments

It’s always fun to look over aerial and satellite maps of places we know, seeing a perspective different from our usual ground level view. We lose that context when it’s a place we don’t know by heart. Such as, say, Mars. So [Matthew Earl] sought to give Perseverance rover’s landing video some context by projecting onto orbital imagery from ESA’s Mars Express. The resulting video (embedded below the break) is a fun watch alongside the technical writeup Reprojecting the Perseverance landing footage onto satellite imagery.

Some telemetry of rover position and orientation were transmitted live during the landing process, with the rest recorded and downloaded later. Surprisingly, none of that information was used for this project, which was based entirely on video pixels. This makes the results even more impressive and the techniques more widely applicable to other projects. The foundational piece is SIFT (Scale Invariant Feature Transform), which is one of many tools in the OpenCV toolbox. SIFT found correlations between Perseverance’s video frames and Mars Express orbital image, feeding into a processing pipeline written in Python for results rendered in Blender.

While many elements of this project sound enticing for applications in robot vision, there are a few challenges touched upon in the “Final Touches” section of the writeup. The falling heatshield interfered with automated tracking, implying this process will need help to properly understand dynamically changing environments. Furthermore, it does not seem to run fast enough for a robot’s real-time needs. But at first glance, these problems are not fundamental. They merely await some motivated people to tackle in the future.

This process bears some superficial similarities to projection mapping, which is a category of projects we’ve featured on these pages. Except everything is reversed (camera instead of video projector, etc.) making the math an entirely different can of worms. But if projection mapping sounds more to your interest, here is a starting point.

[via Dr. Tanya Harrison @TanyaOfMars]

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A Technical (But Not Too Technical) Explanation Of Landing Perseverance Rover On Mars

March 19, 2021 by 6 Comments

There was a lot of enthusiasm surrounding Mars arrival of Perseverance rover, our latest robotic interplanetary explorer. Eager to capitalize on this excitement, NASA JPL released a lot of information to satisfy curiosity of the general public. But making that material widely accessible also meant leaving out many technical details. People who crave just a little more can head over to How NASA’s Perseverance Landed On Mars: An Aerospace Engineer Breaks It Down In Fascinating Detail published by Jalopnik.

NASA JPL’s public materials mostly explained the mission in general terms. Even parts with scientific detail were largely constrained for a target audience of students K-12. Anyone craving more details can certainly find them online, but they would quickly find themselves mired in highly technical papers written by aerospace engineers and planetary geologists for their peers. There is a gap in between those extremes, and this write-up slots neatly in that gap. Author [Brian Kirby] is our helpful aerospace engineer who compiled many technical references into a single narrative of the landing, explained at a level roughly equivalent to undergraduate level math and science courses.

We get more details on why the target landing site is both geologically interesting and technically treacherous, requiring development of new landing smarts that will undoubtedly help future explorers both robotic and human. The complex multi-step transition from orbit to surface is explained in terms of managing kinetic energy. Condensing a wide range of problems to a list of numbers that helps us understand why, for example, a parachute was necessary yet not enough to take a rover all the way to the surface.

Much of this information is known to longtime enthusiasts, but we all had to get our start somewhere. This is a good on-ramp for a new generation of space fans, and together we look forward to Perseverance running down its long and exciting to-do list. Including flying a helicopter, packing up surface samples of Mars, and seeing if we can extract usable oxygen from Martian atmosphere.

Mars 2020 Rover: Curiosity’s Hi-Tech Twin Is Strapped For Science; Includes A Flying Drone

February 13, 2020 by 35 Comments

While Mars may be significantly behind its sunward neighbor in terms of the number of motor vehicles crawling over its surface, it seems like we’re doing our best to close that gap. Over the last 23 years, humans have sent four successful rovers to the surface of the Red Planet, from the tiny Sojourner to the Volkswagen-sized Curiosity. These vehicles have all carved their six-wheeled tracks into the Martian dust, probing the soil and the atmosphere and taking pictures galore, all of which contribute mightily to our understanding of our (sometimes) nearest planetary neighbor.

You’d think then that sending still more rovers to Mars would yield diminishing returns, but it turns out there’s still plenty of science to do, especially if the dream of sending humans there to explore and perhaps live is to come true. And so the fleet of Martian rovers will be joined by two new vehicles over the next year or so, lead by the Mars 2020 program’s yet-to-be-named rover. Here’s a look at the next Martian buggy, and how it’s built for the job it’s intended to do.

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